1. Field of Invention
The invention concerns a tubing set comprising an insert for the infusion of drugs in extracorporeal circuits, in particular a tubing set intended to be used with hemodialysis machines. The invention further concerns a vial suitable for being fitted onto the insert.
2. Description of the Prior Art
In therapeutic treatment that require an extracorporeal circulation it is often necessary to administer different drugs or therapeutic substances to the patient. The presence of the tubing set advantageously makes it possible to avoid the administering of the drug taking place through puncture carried out directly on the patient himself.
As an example, hereafter we consider hemodialysis treatment, without for this reason limiting the scope of the invention to this specific application.
Most of the recent hemodialysis machines, are arranged also for carrying out another treatment, called hemofiltration. Hemofiltration is a renal replacement therapy which is used almost exclusively for acute renal failure. During hemofiltration, a patient's blood is passed through a filter where waste products and water are removed. Due to the water removal, a substitution fluid is needed in addition to the blood which is returned to the patient. Hemofiltration is sometimes used in combination with hemodialysis, originating the so called hemodiafiltration treatment.
In view of the above, recent hemodialysis machines, are provided with a specific circuit intended to deliver the substitution fluid.
In the following, for ease of description, reference will be made to hemodialysis only, however hemofiltration and hemodiafiltration should also be considered within the scope of the present invention.
During such treatments it often becomes necessary to administer different drugs or therapeutic substances, like for example iron, heparin, erythropoietin and vitamin D. The infusion of such substances in the extracorporeal circuit is currently carried out through conventional syringes. The substance is drawn from the vial in which it is supplied by the producer and is then injected into a special puncturable cap provided along the tubing set. Thus there is a double transfer of the substance: firstly from the vial to the syringe and then from the syringe to the circuit.
Such an operation therefore requires the use of disposable materials, such as the syringe and the respective needle, just to transfer the substance from the vial to the tubing set. Moreover, the use of needles always carries the risk of the service staff being pricked.
Furthermore, during the infusion of some therapeutic substances in the patient's blood, attention must be paid in order to avoid hemolysis.
Finally, some of the quoted substances need to be administered slowly, over a few minutes. From this it can easily be understood how the administering of various substances to more than one patient represents a considerable workload for the nursing staff responsible for the treatment.
Two automated processes for delivery of heparin are disclosed in the prior art. A specific pump for acting on the heparin syringe is disclosed in EP 1 909 866. According to this first solution, this specific pump can be used only for heparin, while it can not be used for any other medicament.
A different solution is disclosed in U.S. Pat. No. 5,015,226 wherein the negative pressure induced in the blood conduit by the blood pump is used for sucking the heparin out of the vial. Since the blood pump is located upstream the dialysis filter, this method is only usable with medicaments which can not pass the filter membrane. Furthermore, in such process can be used collapsible vials only, since there is no possibility to effectively suck a medicament out of a rigid vial by way of the negative pressure.
Other tubing sets and the related assemblies for the infusion of substances in the extracorporeal circuit are described in detail in documents U.S. Pat. No. 5,693,008; U.S. Pat. No. 5,983,947; US 2009/0101552 and WO 2008/106191.